POS1210 PATIENTS WITH SUBCLINICAL HEART INVOLVEMENT AT DIAGNOSIS OF MYOSITIS ARE MORE LIKELY TO PRESENT CARDIOVASCULAR EVENTS THAN PATIENTS WITHOUT CARDIAC INVOLVEMENT IN A MONOCENTRIC RETROSPECTIVE STUDY
Authors: C. Kasser, A. F. Guedon, A. Mekinian
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Idiopathic inflammatory myositis (IIM) is a group of rare and heterogeneous systemic diseases characterized by clinical muscle weakness and histological inflammation in skeletal muscles. Myositis classification distinguishes dermatomyositis (DM), inclusion body myositis (IBM), immune-mediated necrotizing myopathy (IMNM), anti synthetase syndrome (ASSD) and overlap myositis (OM) [1-2]. Patients with myositis are more likely to die younger than in general population [3]. Cardiovascular events (CVE) are one of the main causes of death during the disease's course [4]. <h3>Objectives</h3> To investigate the occurrence of CVE and their link with features of cardiac involvement in a French myositis population. <h3>Methods</h3> We conducted a retrospective observational cohort study of patients with a diagnosis of DM, ASSD, IBM, IMNM or OM, from the department of internal medicine in Saint Antoine's hospital, Paris, France, between 1992 and 2020. Demographic and clinical data were collected at diagnosis, at the last follow up visit, and at the first CVE if one happened. Subclinical heart involvement was defined by electrocardiogram abnormality, transthoracic echocardiography abnormality or cardiac MRI abnormality. CVE were defined by the occurrence during the follow up of heart failure, inflammatory myocarditis or admission in resuscitation department. Descriptive, bivariate and survival analysis were performed. <h3>Results</h3> Among the 78 patients included, 52 (67%) were women. Thirty three patients (42%) had a DM, 18 (23%) an ASSD, 12 (15%) an OM, 11 (14%) an IMNM and 4 patients (5%) an IBM. Mean age at diagnosis was 49 years. Median follow up time was 72 months. Subclinical involvement was present at diagnosis for 17 (22%) patients; and 14 (21%) patients presented a CVE during the follow up period. Patients with subclinical cardiac involvement at diagnosis were more likely to present a CVE than patients without subclinical cardiac involvement. Three years after the diagnosis, 7 CVE occurred in the subclinical cardiac involvement group (event rate 37.5%; 95% CI 4.92-58.92) and only 1 CVE occurred in the no cardiac involvement group (event rate 1.89%; 95% CI 0-5.48). Time to CVE was significantly different between groups (log rank test p &lt; 0,001, Graph 1). This difference remains significant at 5 years after myositis diagnosis. <h3>Conclusion</h3> Patients with subclinical cardiac involvement at myositis diagnosis are more likely to present CVE in the first 5 years of disease than patients without subclinical cardiac involvement. Clinical cardiac involvement is rare at diagnostic, but subclinical cardiac involvement seems to be a more frequent condition. Our results suggest that we should pay more attention to patient with subclinical cardiac involvement at myositis diagnosis, especially in the first years of the disease's course. <h3>References</h3> [1]Lundberg IE, Tjärnlund A, Bottai M, Werth VP, Pilkington C, de Visser M, et al. EULAR/ACR Classification Criteria for Adult and Juvenile Idiopathic Inflammatory Myopathies and their Major Subgroups. Ann Rheum Dis. déc 2017;76(12):1955‑64. [2]Mariampillai K, Granger B, Amelin D, Guiguet M, Hachulla E, Maurier F, et al. Development of a New Classification System for Idiopathic Inflammatory Myopathies Based on Clinical Manifestations and Myositis-Specific Autoantibodies. JAMA Neurol. déc 2018;75(12):1528‑37. [3]Dobloug GC, Svensson J, Lundberg IE, Holmqvist M. Mortality in idiopathic inflammatory myopathy: results from a Swedish nationwide population-based cohort study. Annals of the Rheumatic Diseases. 1 janv 2018;77(1):40‑7. [4]Dankó K, Ponyi A, Constantin T, Borgulya G, Szegedi G. Long-Term Survival of Patients With Idiopathic Inflammatory Myopathies According to Clinical Features: A Longitudinal Study of 162 Cases. Medicine. janv 2004;83(1):35. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> None Declared.